Conventionally, when a tip end face of a single core optical connector is cleaned, a cotton swab and the like are used generally. However, a cleaner with a cleaning string is proposed because the conventional technique is insufficient in the wiping performance and depends on an operator's skill (Patent document 1). However, patent document 1 does not disclose specifically about a cleaning string.
Further, as for the cleaning string, a cleaning string formed by aggregating plural chemical fibers having a smaller fiber diameter than an optical fiber diameter without twisting (Patent document 2).